Semiconductor container opening/closing apparatus and semiconductor device manufacturing method

ABSTRACT

A method is provided of manufacturing semiconductor devices formed on a semiconductor wafer, including placing the wafer in a semiconductor container and conveying the container to a semiconductor manufacturing apparatus. An opening of the container is opposed to an opening of the apparatus such that an opener of the apparatus holds a lid of the opening the container. A key of the opener is inserted to a latch groove of the lid, and the key is rotated to contact a latch of the lid. The openings are connected such that a velocity differential pressure ratio obtained by dividing the maximum velocity when the opener holding the lid horizontally moves away from the opening of the container, by the differential pressure between the inside pressure and the outside pressure of the apparatus, is set to be 0.06 ((m/s)/Pa) or less, and then the wafer is processed.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation application of application Ser. No.11/960,804, filed Dec. 20, 2007, which in turn is a continuation ofapplication Ser. No. 11/391,640, filed Mar. 29, 2006 (now U.S. Pat. No.7,314,345), which, is a divisional application of application Ser. No.10/974,819, filed Oct. 28, 2004 (now U.S. Pat. No. 7,048,493), which isa continuation application of application Ser. No. 10/031,785, filedJan. 25, 2002 (now abandoned), the disclosures of which are herebyincorporated by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a semiconductor containeropening/closing apparatus, which opens and closes a lid of asemiconductor wafer container used in a semiconductor manufacturingprocess, and more particularly relates to a semiconductor devicemanufacturing method in which the semiconductor containeropening/closing apparatus is installed in each semiconductormanufacturing apparatus and a semiconductor wafer is conveyed using thesemiconductor wafer container.

BACKGROUND OF THE INVENTION

Recently, in semiconductor manufacturing plants, semiconductor wafersare conveyed between each manufacturing apparatus while being stored insemiconductor containers (hereinafter, referred to as a container) witha lid that isolates the semiconductor wafers from the outer environment.The inside of the container is kept in a very clean condition incomparison to the outside and only a small number of foreign particlesare adhered to the wafer inside the container if the lid of thecontainer is not opened. The condition outside the container is the ISOcleanliness level 6 or the like, and if the wafer is left in such acondition, over time the foreign particles are adhered to a surface ofthe wafer. Consequently, the yield of a semiconductor component formedon the wafer is significantly decreased. The container opening/closingapparatus is provided in each manufacturing apparatus, and the inside ofthe manufacturing apparatus is kept in a very clean condition incomparison to the outside, that is, the ISO cleanliness level 1 to 2.

When the wafer is conveyed from the container to the manufacturingapparatus or from the manufacturing apparatus to the container, themanufacturing apparatus and the container are first connected to eachother via the container opening/closing apparatus. Next, the lid of thecontainer is opened, and thereby it is possible to directly connect theclean area inside the manufacturing apparatus and the clean area insidethe container. Therefore, there is little possibility that the wafer isexposed to the outside air.

The velocity of opening the lid of the container in the conventionalcontainer opening/closing apparatus is set high in order to reduce theoperating time. Also, the conventional container opening/closingapparatus is provided with a safety cover that covers a driving systemin the rear side of the apparatus. As a result, the lower end portion ofthis safety cover has a closed structure.

Conventional container opening/closing apparatuses have suffered fromthe following problem. That is, since the velocity of opening the lid ofthe container is high, the inside of the container is under negativepressure at the time of opening the lid of the container. As a result,foreign particles outside the container enter the container through thegap between the container and the container opening/closing apparatus,and the foreign particles adhere to the wafer.

In addition, another problem also exists in the conventional containeropening/closing apparatus. That is, since a safety cover is provided forthe conventional container opening/closing apparatus to cover thedriving system in the rear side thereof, and since the lower end portionof the safety cover has a closed structure, foreign particles aredeposited inside the safety cover. These foreign particles are blown outwhen a lid elevator unit moves downward, and then enter the container toadhere to the wafer.

An object of the present invention is to reduce the number of foreignparticles adhering to a wafer by preventing the foreign particles fromentering the container at the time of opening the container using thecontainer opening/closing apparatus.

Also, another object of the present invention is to reduce the number offoreign particles adhering to a wafer by preventing the foreignparticles from being deposited inside the safety cover and preventingthe foreign particles from being blown out.

DISCLOSURE OF THE INVENTION

For the achievement of the above objects, the semiconductor containeropening/closing apparatus and a method of opening and closing a lid ofthe semiconductor wafer container according to the present invention arecharacterized in that a velocity-differential pressure ratio obtained bydividing the maximum velocity (m/s) at the time of opening thesemiconductor container, by the differential pressure (Pa) between theinside pressure and the outside pressure of the semiconductormanufacturing apparatus, is set to be 0.006 ((m/s)/Pa) or less.

Also, the semiconductor container opening/closing apparatus according tothe present invention is characterized in that an opening is provided ata lower end portion of the cover in the rear side of the semiconductorcontainer opening/closing apparatus.

Also, the semiconductor container opening/closing apparatus according tothe present invention is characterized in that an exhaust fan isprovided at a lower end portion of the cover in the rear side of thesemiconductor container opening/closing apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a semiconductor containeropening/closing apparatus according to a first embodiment of the presentinvention,

FIG. 2 is a perspective view of a semiconductor container,

FIG. 3 is a perspective view of a semiconductor manufacturing apparatusin which semiconductor container opening/closing apparatuses accordingto a first embodiment of the present invention are installed,

FIG. 4 is a conceptual graph showing the correlation between the maximumvelocity of opening the semiconductor container and the number offoreign particles adhering to a wafer,

FIG. 5 is a conceptual view showing, relative to change of time, thevelocity of opening the container by the semiconductor containeropening/closing apparatus according to a first embodiment of the presentinvention,

FIG. 6 is a conceptual graph showing, relative to change of time, thevelocity of opening the container by the conventional semiconductorcontainer opening/closing apparatus,

FIG. 7 is a conceptual graph showing the correlation between the maximumvelocity of opening the semiconductor container and the number offoreign particles adhering to a wafer, and

FIG. 8 is a conceptual graph showing the correlation between the maximumvelocity of opening the semiconductor container and the number offoreign particles adhering to the wafer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For a more detailed description of a first embodiment of the presentinvention, the first embodiment will be described based on theaccompanying drawings (FIGS. * 1 to 8).

FIG. 1 is a perspective view of a semiconductor containeropening/closing apparatus (hereinafter, referred to as anopening/closing apparatus) according to the first embodiment of thepresent invention, FIG. 2 is a perspective view of a semiconductorcontainer (hereinafter, referred to as a container), FIG. 3 is aperspective view of a semiconductor manufacturing apparatus(hereinafter, referred to as a manufacturing apparatus) in which theopening/closing apparatuses are installed, FIGS. 4, 7, and 8 areconceptual graphs each showing the correlation between the maximumvelocity of opening the container and the number of foreign particlesadhering to a wafer, FIG. 5 is a conceptual graph showing, relative tochange of time, the velocity of opening the container by theopening/closing apparatus according to the first embodiment of thepresent invention, and FIG. 6 is a conceptual graph showing, relative toa change of time, the velocity of opening the container by theconventional opening/closing apparatus.

Descriptions will be first made of respective structures of anopening/closing apparatus 100 and a container 200 by using FIGS. 1 and2. The opening/closing apparatus 100 is mainly constituted by a stage110 for placing the container 200, and an opener 120 for holding a lid220 of the container 200 and for opening and closing the lid 220. Thestage 110 is provided with positioning pins 112 for placing thecontainer 200 in a proper position, and a slider 111 for bringing thecontainer 200 closer to an opener 120. In this embodiment, the slider111 is movable back and forth by a motor and a ball screw (not shown)provided in the stage 110. Rotating keys 121 are provided on the opener120, and the rotating keys 121 can rotate up to 90 degrees by a motor(not shown) provided in the opener 120. In the rear side of the opener120, an opener opening/closing mechanism 130 for opening and closing thelid 220 of the container 200 by making the opener 120 move back andforth horizontally, and an opener elevator mechanism 131 for moving theopener 120 up and down are provided. Both of the opener opening/closingmechanism 130 and the opener elevator mechanism 131 are operated by amotor and a ball screw (not shown), and a safety cover 140 is providedon the whole of both driving units of the opener opening/closingmechanism 130 and the opener elevator mechanism 131 so that anoperator(s) can not touch them easily.

The container 200 is constituted by a container body 210 and the lid220. The container body 210 is provided with four latch grooves 211, anda flange 212 is provided around the container body 210. A shelf (notshown) is provided inside the container body 210 for storing wafers 300horizontally, and twenty-five wafers can be stored therein. Key grooves221 are provided on the lid 220 at positions corresponding to those ofthe rotating keys 121 of the opening/closing apparatus 100. The rotatingkeys 121 of the opening/closing apparatus 100 are inserted into the keygrooves 221 and rotated by 90 degrees. By virtue of this, four latches222 in the lid 220 come in and out from the lid 220 by a cam mechanism(not shown) operating inside the lid 220. The latches 222 are atpositions corresponding to those of the latch grooves 211 of thecontainer body 210, and when the latches 222 come out from the peripheryof the lid 220 while the lid 220 is inserted in the container body 210,the lid 220 can be fixed to the container body 210.

The actual operation of opening the container 200 is carried out asfollows. The container 200 is placed on the stage 110. The slider 111 onthe stage 110 is moved horizontally toward the manufacturing apparatus,and a surface of the lid 220 of the container 200 and the opener 120 ofthe opening/closing apparatus 100 are contacted to each other. At thistime, though the flange 212 of the container 200 and a surface board 150of the opening/closing apparatus 100 are partly contacted to each other,a gap is inevitably left therebetween due to the process accuracy of thecontainer 200. When the rotating keys 121 are rotated by 90 degrees inthe clockwise direction toward the container 200 while the lid 220 andthe opener 120 are contacted to each other, the key grooves 221 of thelid 220 are rotated and the lid 220 is fixed to the opener 120.Simultaneously, the latches 222 are accommodated inside the lid 220 by afunction of the cam mechanism (not shown) inside the lid 220.Thereafter, the opener opening/closing mechanism 130 is horizontallymoved toward the manufacturing apparatus to detach the lid 220 of thecontainer 200 from the container body 210. Specifically, the lid 220 ofthe semiconductor container 200 is held and opened in a directionvertical to an opening surface of the container 200. Then, the opener120 is moved downward by the opener elevator mechanism 131.

The operation of closing the container 200 is carried out in a reversemanner to the operation of opening the same, in which, after the openerelevator mechanism 131 is moved upward, the opener opening/closingmechanism 130 is moved horizontally toward the stage 110 to connect, tothe container body 210, the lid 220 fixed to the opener 120. Thereafter,when the rotating keys 121 are rotated by 90 degrees in thecounterclockwise direction, the latches 222 of the lid 220 are fit intothe latch grooves 211 on the container body 210. Thus, the lid 220 isfixed to the container body 210. Finally, the slider 111 is movedhorizontally in a direction opposite to the manufacturing apparatus,and, thereby, the container 200 is put into a state where it can bedetached from the stage 110.

FIG. 3 shows an example where four opening/closing apparatuses 100 aremounted to a manufacturing apparatus 400. Downflow is formed inside themanufacturing apparatus 400, and the inside of the apparatus 400 is keptin the ISO cleanliness level 1 to 2, that is, the inside thereof is keptin a very clean condition in comparison to the outside of themanufacturing apparatus 400 which is in the ISO cleanliness level 6. Ifa wafer is left in the environment of the ISO cleanliness level 6, overtime foreign particles adhere to a wafer surface. As a result, the yieldof semiconductor components formed on the wafer is significantlydecreased. The inside of the container 200 is shielded from the outsidethereof, and if the wafer 300 is loaded and unloaded in thehigh-cleanliness environment, the cleanliness inside the container ismaintained. Therefore, even if the container 200 is left in theenvironment of the ISO cleanliness level 6, only a small number offoreign particles adhere to the wafer 300 inside the container 200unless the lid 220 of the container 200 is opened or closed.

When the wafer 300 is moved from the container 200 to the manufacturingapparatus 400 or from the manufacturing apparatus 400 to the container200, the lid 220 of the container 200 is opened or closed afterconnection of the manufacturing apparatus 400 and the container 200 viathe container opening/closing apparatus 100. Thus, a clean area insidethe manufacturing apparatus 400 and a clean area inside the container200 are directly connected to each other. Since the pressure inside themanufacturing apparatus 400 is set to a slightly positive pressure incomparison to the outside thereof, there is little possibility that theforeign particles will flow through the gap between the flange 211 ofthe container 200 and the surface board 150 of the opening/closingapparatus 100, except at the moment of opening or closing the container200.

If the operating velocity of the opener opening/closing mechanism 130 ofthe opening/closing apparatus 100 is high, then the inside of thecontainer 200 experiences a negative pressure at the time of pulling outthe lid 220 from the container body 210, and the foreign particles enterinto the container 200 through the gap between the flange 211 of thecontainer 200 and the surface board 150 of the opening/closing apparatus100, and adhere to the wafer 300.

FIG. 5 shows, relative to the change with time, the velocity of openingthe container 200 by the opener opening/closing mechanism 130 of theopening/closing apparatus 100 according to the present invention. InFIG. 5, the horizontal axis represents time (s) and the vertical axisrepresents the velocity of opening (m/s), and the maximum velocity is0.025 (m/s). FIG. 6 shows, relative to the change with time, thevelocity of opening the container 200 by the opener opening/closingmechanism 130 of the conventional opening/closing apparatus 100. In FIG.6, the horizontal axis represents time (s) and the vertical axisrepresents the velocity of opening (m/s), and the maximum velocity is0.15 (m/s).

FIG. 4 is a conceptual graph showing the correlation between the maximumvelocity of opening the container and the number of foreign particlesadhering to a wafer stored in the container when the inside pressure ofthe apparatus 400 is higher by 1 (Pa) than the pressure of the outside.In FIG. 4, the horizontal axis represents the maximum velocity (m/s) ofopening the container by the opener opening/closing mechanism 130, andthe vertical axis represents the number of foreign particles(Number/WaferTimes) which have a grain size of 0.12 pm or more and whichadhere to the uppermost wafer 300 stored in the container 200 peropening/closing of the container 200. FIG. 7 is a conceptual graphshowing the correlation between the maximum velocity of opening andclosing the container and the number of foreign particles adhering to awafer when the inside pressure of the apparatus 400 is higher by 5 (Pa)than the pressure of the outside. The vertical and horizontal axes ofFIG. 7 represent the same variables as those of FIG. 4. FIG. 8 shows aconceptual graph showing the correlation between the maximum velocity ofopening and closing the container and the number of foreign particlesadhered to a wafer when the inside pressure of the apparatus 400 ishigher by 10 (Pa) than the pressure of the outside. The vertical andhorizontal axes of FIG. 8 represent the same variables as those of FIGS.4 and 7.

In FIG. 4, the number of foreign particles adhering to the wafer 300exceeds 0.01 (Number/WaferTimes) at the maximum velocity of 0.06 (m/s),and it rapidly increases if the maximum velocity is over 0.06 (m/s). InFIG. 7, the number of foreign particles exceeds 0.01 (Number/WaferTimes)at the maximum velocity of 0.3 (m/s), and in FIG. 8, the number offoreign particles exceeds 0.01 (Number/WaferTimes) at the maximumvelocity of 0.& (m/s). As is apparent from FIGS. 4, 7, and 8, it can beunderstood that the maximum velocity, at which the number of foreignparticles increases, becomes higher in proportion to the differentialpressure between the inside pressure and the outside pressure of theapparatus 400.

The number of foreign particles adhering to the wafer 300 can be reducedby decreasing the maximum velocity of opening of the container by theopener opening/closing mechanism 130. However, the slow operatingvelocity in each unit of the opening/closing apparatus 100 influencesthe process faculty of the manufacturing apparatus 400 per unit time.Therefore, it is required to set the operating velocity in anappropriate range. For this reason, it is conceived that the operatingvelocity should be set in a certain range capable of sufficientlyassuring the operation ability of the semiconductor manufacture, andalso be set lower than the operating velocity at which the number offoreign particles is 0.01 (Number/WaferTimes), which is a boundary atwhich the number of foreign particles adhering to the wafer begins torapidly increase in all of FIGS. 4, 7, and 8. Since the differentialpressure between the inside pressure and the outside pressures of theapparatus 400 is proportional to the maximum velocity at which thenumber of foreign particles begins to increase, the number of foreignparticles adhering to the wafer surface can be suppressed by setting aratio (velocity-differential pressure ratio Dvp) between the Vmax:maximum velocity (m/s) of opening the container by the openeropening/closing mechanism 130 and APa: differential pressure (Pa)between the inside pressure of the apparatus 400 and the outsidepressure so as to satisfy the formula I shown below:

Vmax/APa=Dvp˜0.06,

where APa: differential pressure (Pa) between the inside pressure of theapparatus 400 and the outside pressure, Vmax: maximum velocity (m/s) ofopening the container by the opener opening/closing mechanism 130, andDvp: velocity-differential pressure ratio (m/sPa).

In this embodiment, since the velocity-differential pressure ratio iswithin the range defined by formula 1, the number of foreign particlesadhering to the wafer 300 stored in the container 200 can be reduced.Therefore, the yield of the semiconductor component can be improved.

Note that this embodiment is an example where the condition outside thecontainer is in the ISO cleanliness level 6, and the number of foreignparticles adhering to the wafer changes depending on changes in thesurrounding condition. However, the maximum velocity at which the numberof foreign particles adhering to the wafer begins to rapidly increase isalways constant.

By providing a packing at a contact position between a surface plate 150of the opening/closing apparatus 100 and a flange 212 of the container200, and by filling the gap between the surface plate 150 and the flange212, the foreign particles which enter into the container at the time ofopening the lid 220 of the container 200 are shut out. Thus, the numberof foreign particles adhering to the wafer 300 can be reduced. If thepacking is provided, however, the following problems are created. Thatis, one problem is that the packing itself generates dust due to thedeterioration caused by the change with time and to repetitive use ofthe packing. Thus, there is an increase in the number of foreignparticles adhering to the wafer. Another problem is that the cost isincreased due to the additional cost required to provide the packingitself, to process the surface plate, and to install the packing. Sincethe packing is not required in this embodiment, the reliability is highand the cost is low.

Also, in another embodiment (second embodiment) of the presentinvention, an opening is provided at a lower end portion of the safetycover 140 of the opening/closing apparatus 100. In the conventionalsafety cover 140, the opening is provided at only the upper end portionof the safety cover. Therefore, a problem has arisen that the foreignparticles generated from the opener opening/closing mechanism 130, theopener elevator mechanism 131, or the like are deposited inside thesafety cover 140. As a result, the deposited foreign particles are blownout at the time when the opener elevator mechanism 131 moves downward,and enter the container 200 and adhere to the wafer. In this embodiment,since the opening is provided at the lower end portion of the safetycover 140, the foreign particles are not deposited inside the safetycover and are not blown out. Therefore, the number of foreign particlesadhering to the wafer 300 stored in the container 200 can be reduced,and thus the yield of the semiconductor component can be improved.

The safety cover 140 covers the driving systems of the openeropening/closing mechanism 130 and the opener elevator mechanism 131 inorder to ensure safety of an operator and to protect the driving systemsat the time of conveying the opening/closing apparatus 100. Therefore,even if the opening is provided at the lower end portion of the safetycover 140, the safety cover does not lose its essential function.

Also, in this embodiment, the opening is simply provided at the lowerend portion of the safety cover 140. However, the same effect can beexpected by providing an exhaust fan at the lower end portion of thesafety cover 140.

INDUSTRIAL APPLICABILITY

As described above, according to the present invention, it is possibleto reduce the number of foreign particles entering into the container atthe time of opening the container, and, therefore, the number of foreignparticles adhering to the wafer can be reduced and the yield of thesemiconductor component can be improved. In addition, since a packing isnot required, an opening/closing apparatus having high reliability canbe realized at low cost.

Also, according to the present invention, since the foreign particlesare not deposited inside the safety cover, the foreign particles are notblown out, and, thus, the number of foreign particles adhering to thewafer can be reduced. Therefore, the yield of the semiconductorcomponent can be improved.

1. A method of manufacturing a plurality of semiconductor devices formedon a semiconductor wafer, comprising: accommodating the semiconductorwafer in a semiconductor container; conveying the semiconductorcontainer to a semiconductor manufacturing apparatus; opposing anopening of the semiconductor container to an opening of thesemiconductor manufacturing apparatus in proximity to each other in sucha manner that an opener of the semiconductor manufacturing apparatusholds a lid of the opening of the semiconductor container; moving downthe opener holding the lid of the semiconductor container by an openerelevator mechanism so that the opener and the opener elevator mechanismare located inside a cover having an opening and an exhaust fan providedat a lower end portion of the cover; processing the semiconductor waferaccommodated in the semiconductor container.
 2. A method ofmanufacturing a plurality of semiconductor devices formed on asemiconductor wafer, comprising: placing a semiconductor containeraccommodating a semiconductor wafer on a stage; connecting an opening ofthe semiconductor container and an opening of a semiconductormanufacturing apparatus; holding a lid of said semiconductor containerby an opener; opening the lid in a direction vertical to an openingsurface of the container by the opener so as to connect the opening ofthe semiconductor container and the opening of the semiconductormanufacturing apparatus while both of the openings are opened; movingdown the opener holding the lid of the semiconductor container by anopener elevator mechanism so that the opener and the opener elevatormechanism are located inside a cover having an opening provided at alower end portion of the cover; processing the semiconductor waferaccommodated in the semiconductor container.
 3. A method ofmanufacturing a plurality of semiconductor devices formed on asemiconductor wafer according to claim 2, wherein an exhaust fan isprovided at a lower end portion of the cover.